The CMB Infectious Disease Pathogenesis Section assisted Principal Investigators with experimental design, tissue collection and preparation, interpretation of histopathology findings, and assistance with manuscript preparation. CMB Research Support Specialists also provided technical expertise and support to NIAID Principal Investigators. Both pathology and technical proficiency resulted in numerous co-authorship opportunities. The CMB has undertaken the challenge of bringing a gnotobiotic facility on line and will initiate internal breeding. The CMB has an active Assisted Reproduction Technologies and Cryopreservation unit. Last year the ARTiC group froze 7922 embryos of 32 mouse lines from 12 different PIs. This year we have banked 3000 embryos of 15 lines and have 13 lines in the pipeline. Last year we froze the sperm of 25 mouse strains for 9 PIs, this year we froze the sperm of 42 lines for 21 different PIs. Last year we had 51 rederivations and we have 25 so far this year. The ARTic group will be conducting a sperm cryopreservation workshop for the local AALAS chapter and give a talk on cryopreservation during their annual meeting;we also are going to present a poster at the ISTT meeting next October. We have found spontaneous intracardiac thrombosis and aortic aneurysms in tamarins. A mission of the Comparative Medicine Branch (CMB) is to provide support to the emerging and re-emerging infectious disease research conducted within the NIAID/DIR Animal Biosafety Level (ABSL) 3 facilities. An example that illustrates the type of research support provided is the formation of the necropsy team. A team of CMB Veterinarians spent several months performing and perfecting numerous non human primate (NHP) necropsies in preparation to support a complex neurovirulent study. The study required the meticulous removal of brain and spinal cord from NHPs for evaluation by laboratory personnel. The necropsy team successfully performed all NHP necropsies including brain, spinal cord, and other organ removal for the entire study. Members of the Comparative Medicine Branch (CMB) along with a Division of Occupational Health and Safety (DOHS) representative have submitted a manuscript to the Journal of the American Association for Laboratory Animal Science (JAALAS) providing a background of laws, regulations, and an overview of programmatic requirements pertaining to the use of Select Agents. The manuscript is currently under review.